linux/drivers/rtc/rtc-dev.c

492 lines
11 KiB
C

/*
* RTC subsystem, dev interface
*
* Copyright (C) 2005 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* based on arch/arm/common/rtctime.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include "rtc-core.h"
static dev_t rtc_devt;
#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
static int rtc_dev_open(struct inode *inode, struct file *file)
{
int err;
struct rtc_device *rtc = container_of(inode->i_cdev,
struct rtc_device, char_dev);
const struct rtc_class_ops *ops = rtc->ops;
/* We keep the lock as long as the device is in use
* and return immediately if busy
*/
if (!(mutex_trylock(&rtc->char_lock)))
return -EBUSY;
file->private_data = rtc;
err = ops->open ? ops->open(rtc->dev.parent) : 0;
if (err == 0) {
spin_lock_irq(&rtc->irq_lock);
rtc->irq_data = 0;
spin_unlock_irq(&rtc->irq_lock);
return 0;
}
/* something has gone wrong, release the lock */
mutex_unlock(&rtc->char_lock);
return err;
}
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
/*
* Routine to poll RTC seconds field for change as often as possible,
* after first RTC_UIE use timer to reduce polling
*/
static void rtc_uie_task(struct work_struct *work)
{
struct rtc_device *rtc =
container_of(work, struct rtc_device, uie_task);
struct rtc_time tm;
int num = 0;
int err;
err = rtc_read_time(rtc, &tm);
local_irq_disable();
spin_lock(&rtc->irq_lock);
if (rtc->stop_uie_polling || err) {
rtc->uie_task_active = 0;
} else if (rtc->oldsecs != tm.tm_sec) {
num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
rtc->oldsecs = tm.tm_sec;
rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
rtc->uie_timer_active = 1;
rtc->uie_task_active = 0;
add_timer(&rtc->uie_timer);
} else if (schedule_work(&rtc->uie_task) == 0) {
rtc->uie_task_active = 0;
}
spin_unlock(&rtc->irq_lock);
if (num)
rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
local_irq_enable();
}
static void rtc_uie_timer(unsigned long data)
{
struct rtc_device *rtc = (struct rtc_device *)data;
unsigned long flags;
spin_lock_irqsave(&rtc->irq_lock, flags);
rtc->uie_timer_active = 0;
rtc->uie_task_active = 1;
if ((schedule_work(&rtc->uie_task) == 0))
rtc->uie_task_active = 0;
spin_unlock_irqrestore(&rtc->irq_lock, flags);
}
static void clear_uie(struct rtc_device *rtc)
{
spin_lock_irq(&rtc->irq_lock);
if (rtc->irq_active) {
rtc->stop_uie_polling = 1;
if (rtc->uie_timer_active) {
spin_unlock_irq(&rtc->irq_lock);
del_timer_sync(&rtc->uie_timer);
spin_lock_irq(&rtc->irq_lock);
rtc->uie_timer_active = 0;
}
if (rtc->uie_task_active) {
spin_unlock_irq(&rtc->irq_lock);
flush_scheduled_work();
spin_lock_irq(&rtc->irq_lock);
}
rtc->irq_active = 0;
}
spin_unlock_irq(&rtc->irq_lock);
}
static int set_uie(struct rtc_device *rtc)
{
struct rtc_time tm;
int err;
err = rtc_read_time(rtc, &tm);
if (err)
return err;
spin_lock_irq(&rtc->irq_lock);
if (!rtc->irq_active) {
rtc->irq_active = 1;
rtc->stop_uie_polling = 0;
rtc->oldsecs = tm.tm_sec;
rtc->uie_task_active = 1;
if (schedule_work(&rtc->uie_task) == 0)
rtc->uie_task_active = 0;
}
rtc->irq_data = 0;
spin_unlock_irq(&rtc->irq_lock);
return 0;
}
#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
static ssize_t
rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct rtc_device *rtc = to_rtc_device(file->private_data);
DECLARE_WAITQUEUE(wait, current);
unsigned long data;
ssize_t ret;
if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
return -EINVAL;
add_wait_queue(&rtc->irq_queue, &wait);
do {
__set_current_state(TASK_INTERRUPTIBLE);
spin_lock_irq(&rtc->irq_lock);
data = rtc->irq_data;
rtc->irq_data = 0;
spin_unlock_irq(&rtc->irq_lock);
if (data != 0) {
ret = 0;
break;
}
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
schedule();
} while (1);
set_current_state(TASK_RUNNING);
remove_wait_queue(&rtc->irq_queue, &wait);
if (ret == 0) {
/* Check for any data updates */
if (rtc->ops->read_callback)
data = rtc->ops->read_callback(rtc->dev.parent,
data);
if (sizeof(int) != sizeof(long) &&
count == sizeof(unsigned int))
ret = put_user(data, (unsigned int __user *)buf) ?:
sizeof(unsigned int);
else
ret = put_user(data, (unsigned long __user *)buf) ?:
sizeof(unsigned long);
}
return ret;
}
static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
{
struct rtc_device *rtc = to_rtc_device(file->private_data);
unsigned long data;
poll_wait(file, &rtc->irq_queue, wait);
data = rtc->irq_data;
return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
}
static int rtc_dev_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int err = 0;
struct rtc_device *rtc = file->private_data;
const struct rtc_class_ops *ops = rtc->ops;
struct rtc_time tm;
struct rtc_wkalrm alarm;
void __user *uarg = (void __user *) arg;
/* check that the calling task has appropriate permissions
* for certain ioctls. doing this check here is useful
* to avoid duplicate code in each driver.
*/
switch (cmd) {
case RTC_EPOCH_SET:
case RTC_SET_TIME:
if (!capable(CAP_SYS_TIME))
return -EACCES;
break;
case RTC_IRQP_SET:
if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
return -EACCES;
break;
case RTC_PIE_ON:
if (!capable(CAP_SYS_RESOURCE))
return -EACCES;
break;
}
/* avoid conflicting IRQ users */
if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
spin_lock_irq(&rtc->irq_task_lock);
if (rtc->irq_task)
err = -EBUSY;
spin_unlock_irq(&rtc->irq_task_lock);
if (err < 0)
return err;
}
/* try the driver's ioctl interface */
if (ops->ioctl) {
err = ops->ioctl(rtc->dev.parent, cmd, arg);
if (err != -ENOIOCTLCMD)
return err;
}
/* if the driver does not provide the ioctl interface
* or if that particular ioctl was not implemented
* (-ENOIOCTLCMD), we will try to emulate here.
*/
switch (cmd) {
case RTC_ALM_READ:
err = rtc_read_alarm(rtc, &alarm);
if (err < 0)
return err;
if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
return -EFAULT;
break;
case RTC_ALM_SET:
if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
return -EFAULT;
alarm.enabled = 0;
alarm.pending = 0;
alarm.time.tm_wday = -1;
alarm.time.tm_yday = -1;
alarm.time.tm_isdst = -1;
/* RTC_ALM_SET alarms may be up to 24 hours in the future.
* Rather than expecting every RTC to implement "don't care"
* for day/month/year fields, just force the alarm to have
* the right values for those fields.
*
* RTC_WKALM_SET should be used instead. Not only does it
* eliminate the need for a separate RTC_AIE_ON call, it
* doesn't have the "alarm 23:59:59 in the future" race.
*
* NOTE: some legacy code may have used invalid fields as
* wildcards, exposing hardware "periodic alarm" capabilities.
* Not supported here.
*/
{
unsigned long now, then;
err = rtc_read_time(rtc, &tm);
if (err < 0)
return err;
rtc_tm_to_time(&tm, &now);
alarm.time.tm_mday = tm.tm_mday;
alarm.time.tm_mon = tm.tm_mon;
alarm.time.tm_year = tm.tm_year;
err = rtc_valid_tm(&alarm.time);
if (err < 0)
return err;
rtc_tm_to_time(&alarm.time, &then);
/* alarm may need to wrap into tomorrow */
if (then < now) {
rtc_time_to_tm(now + 24 * 60 * 60, &tm);
alarm.time.tm_mday = tm.tm_mday;
alarm.time.tm_mon = tm.tm_mon;
alarm.time.tm_year = tm.tm_year;
}
}
err = rtc_set_alarm(rtc, &alarm);
break;
case RTC_RD_TIME:
err = rtc_read_time(rtc, &tm);
if (err < 0)
return err;
if (copy_to_user(uarg, &tm, sizeof(tm)))
return -EFAULT;
break;
case RTC_SET_TIME:
if (copy_from_user(&tm, uarg, sizeof(tm)))
return -EFAULT;
err = rtc_set_time(rtc, &tm);
break;
case RTC_IRQP_READ:
if (ops->irq_set_freq)
err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
else
err = -ENOTTY;
break;
case RTC_IRQP_SET:
if (ops->irq_set_freq)
err = rtc_irq_set_freq(rtc, rtc->irq_task, arg);
break;
#if 0
case RTC_EPOCH_SET:
#ifndef rtc_epoch
/*
* There were no RTC clocks before 1900.
*/
if (arg < 1900) {
err = -EINVAL;
break;
}
rtc_epoch = arg;
err = 0;
#endif
break;
case RTC_EPOCH_READ:
err = put_user(rtc_epoch, (unsigned long __user *)uarg);
break;
#endif
case RTC_WKALM_SET:
if (copy_from_user(&alarm, uarg, sizeof(alarm)))
return -EFAULT;
err = rtc_set_alarm(rtc, &alarm);
break;
case RTC_WKALM_RD:
err = rtc_read_alarm(rtc, &alarm);
if (err < 0)
return err;
if (copy_to_user(uarg, &alarm, sizeof(alarm)))
return -EFAULT;
break;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
case RTC_UIE_OFF:
clear_uie(rtc);
return 0;
case RTC_UIE_ON:
return set_uie(rtc);
#endif
default:
err = -ENOTTY;
break;
}
return err;
}
static int rtc_dev_release(struct inode *inode, struct file *file)
{
struct rtc_device *rtc = to_rtc_device(file->private_data);
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
clear_uie(rtc);
#endif
if (rtc->ops->release)
rtc->ops->release(rtc->dev.parent);
mutex_unlock(&rtc->char_lock);
return 0;
}
static int rtc_dev_fasync(int fd, struct file *file, int on)
{
struct rtc_device *rtc = to_rtc_device(file->private_data);
return fasync_helper(fd, file, on, &rtc->async_queue);
}
static const struct file_operations rtc_dev_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = rtc_dev_read,
.poll = rtc_dev_poll,
.ioctl = rtc_dev_ioctl,
.open = rtc_dev_open,
.release = rtc_dev_release,
.fasync = rtc_dev_fasync,
};
/* insertion/removal hooks */
void rtc_dev_prepare(struct rtc_device *rtc)
{
if (!rtc_devt)
return;
if (rtc->id >= RTC_DEV_MAX) {
pr_debug("%s: too many RTC devices\n", rtc->name);
return;
}
rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
mutex_init(&rtc->char_lock);
spin_lock_init(&rtc->irq_lock);
init_waitqueue_head(&rtc->irq_queue);
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
INIT_WORK(&rtc->uie_task, rtc_uie_task);
setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
#endif
cdev_init(&rtc->char_dev, &rtc_dev_fops);
rtc->char_dev.owner = rtc->owner;
}
void rtc_dev_add_device(struct rtc_device *rtc)
{
if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
rtc->name, MAJOR(rtc_devt), rtc->id);
else
pr_debug("%s: dev (%d:%d)\n", rtc->name,
MAJOR(rtc_devt), rtc->id);
}
void rtc_dev_del_device(struct rtc_device *rtc)
{
if (rtc->dev.devt)
cdev_del(&rtc->char_dev);
}
void __init rtc_dev_init(void)
{
int err;
err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
if (err < 0)
printk(KERN_ERR "%s: failed to allocate char dev region\n",
__FILE__);
}
void __exit rtc_dev_exit(void)
{
if (rtc_devt)
unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
}